----- Original Message -----
From: "Andy Armstrong" <[EMAIL PROTECTED]>
To: "Lionel MARTIN" <[EMAIL PROTECTED]>
Cc: <modperl@perl.apache.org>
Sent: Friday, May 11, 2007 12:34 AM
Subject: Re: After retrieving data from DB, the memory doesn't seem to be
freed up
On 10 May 2007, at 23:25, Lionel MARTIN wrote:
OK, fine.
So, to sum up, if I have got 10 different scripts in a mod perl
environment (let's call them test1.pl....test10.pl), and using lexical
variables there.
If I first run test1.pl and then, run test2.pl, the only way for test2.p
to get access to the memory used by test2.pl is freeing up test1.pl
lexical variables, by undefining them?
And what if I run test1.pl twice without undefining its lexical
variables? Will the same memory space be used twice, or will each call
use different memory space (I'm talking here about situation where the
same Perl interpreter is running the script twice in a mod perl
environment)?
The memory allocated /directly/ to a lexical remains allocated at the end
of the scope on the assumption that it might be needed again in the
future. That's so that when you call something like
sub string_builder {
my $s = '';
$s .= 'x' for 1 .. 1_000_000;
return $s;
}
repeatedly it's able to reuse memory from the previous invocation rather
than allocating it all from scratch each time. That's mainly a
performance optimisation.
However memory referred to indirectly as in your example
$x = [ 1 .. 1_000_000 ];
is freed as soon as nothing refers to it any more. So when $x goes out of
scope that storage /is/ freed - to Perl at least.
Please don't get the idea that Perl never frees anything and please don't
start littering your code with unnecessary explicit memory management.
--
Andy Armstrong, hexten.net
That's why I have been asking all these questions. That's only when
understanding things that you don't do unnecessary or take counter
productive measures.
Thanks,
Lionel.
